Flap control mechanism



P 1939. 1. M. LADDON ET AL FLAP CONTROL MECHANISM Filed NOV. 18, 1936lNVENTORS M. LADDON 8 H. K.GRO WALD.

' ATTORNEY' Patented Sept. 26, 1939 PATENT OFFICE FLAP comm. MECHANISMIsaac M. Laddon,

Wald, Mission Beach,

San Diego, and Henry K. Gro- Calif., assignors to Consolidated AircraftCorporation, a corporation of Delaware Application November 18, 1936,Serial No. 111,414

16 Claims.

This invention relates to control surfaces and flaps for aircraftwherein an auxiliary flap moves in conjunction with a main controlsurface and more particularly to constructions and. operating mechanismwhereby an auxiliary flap may be preset or adjusted at will to assumevarying angular dispositions with respect to the movable controlsurface.

An object of our invention lies in the provision of means for adjustingthe auxiliary flap position whereby the auxiliary flap progressivelyincreases its angular deviation with continued movement of the movablesurface and conversely on return movement automatically decreases theangular deviation until a point is reached, depending on the originalpre-set angle, where the moving surface and its auxiliary flap lie onthe same longitudinal axis i. e., where the median lines of each arealin'ed and continuous.

control mechanism whereby, whenever the movable surface exceeds apredetermined angle with respect to its normal position, the auxiliaryflap is automatically released from thepre-set align-- lar. displacementand returned to its neutral position on an axis parallel to that of themovable surface.

Still another object of our invention is to provide in an airfoil amethod of varying the cambar thereof to provide an airfoil shape whichwill have high lift characteristics for landing and take-01f purposes,yet which can be instantaneously restored to its normal high speedcharacteristic.

, A further object is to provide a flap of a type adapted to be used inpairs as ailerons and having a relative differential movement withrespect to each other such that the downwardly moving flap changes itsangular deviation from the neu- 40' tral axis at a greater rate thandoes the upwardly moving flap.

These and other objects of our invention will be better understood fromthe following description and drawing of embodiments thereof in whichlike numbers designate like'parts and in which,

Fig. 1 shows in cross-section, an airfoil comprising a main section, amovable surface, and

w an auxiliary flap adapted for differential movement with the saidsurface,

Fig. 2 shows a progressive development of the airfoil shown in Fig. 1wherein is provided an automatic release device operating by reason ofthe above mentioned differential action, and

A further object of our invention is to provide Fig. 3 illustrates indetail the release device as incorporated in the construction of Fig. 2.

The airfoil Ill has a relativelyfixed main section ll, an. intermediatepivotal section l2, which hereafter will be termed the movable surfaceI2, 5 and a trailing section or flap l3; the three sections in theirrelationship with each other pre- 7 senting' a typical airfoil section.

The movable intermediate surface I2 is pivoted at 14 to the main sectionII and is provided with 10 horns l5 and I6 connecting to cables l1 and[8 respectively which run over the sheaves I9 and 20 to the pilotscockpit terminating there in a control means of conventional type nowwidely used on ailerons or other movable surfaces. Thus 15 it isapparent that a pull transmitted through cable ll will effect a raisingof the movable surface |2 to some new position angularly above itsnormal axis N--N and in the same manner cable l8 serves to position themovable surface 20 I2 obliquely to and below the normal position N-N. I

Within the fixed wing section II is mounted pulley 2|, or anysuitablemeans by which rotary motion can be' transmitted from the pilots25 cockpit to the shaft 22. Bearings 23 and 24 mounted on crosspieces orspars Ila of the wing section support shaft 22 and collars 25 thereonprevent axial play of the shaft 22 and hence its only possible motion isone of revolution. Shaft 30 22 terminates in the universal joint 26.

Just as the movable surface I2 is pivoted to the main section II by apivot l4, so also is the flap l3 in turn pivoted to the movable surfacel2 through the pivot 21. This pivot 21 may lie on the axis of symmetryof flap l3 or it may be offset somewhat as dictated by designconsiderations.

Referring particularly to Fig. 1 it is seen that the control means forflap l3 comprises a turnbuckle device 29, pivotally connecting to theflap l3 at pivot 30. The turnbuckle 29 has a rodlike extension 290.connecting to the previously mentioned universal joint 26, hence onrotation of pulley 2|, the torque thereof is transmitted through shaft22, universal joint 26, and rod 29a to turnbuckle 29, resulting in anextension or contraction of the latter which causes the flap l3 to moveabout its pivot 21 and assume an I oblique position relative to itsnormal in-line" position with movable surface I2. To prevent separationthreaded end of rod 29a. carries slidable in a slotted portion of, theturnbuckle body which prevents separation of the parts and maximum throwof the flap surface it, to some angle such automatic differentialmovement between flap is and surface l2 the pivotal center of joint 26must be ofiset from the pivot I4. Then with the flap l3 pre-set to someangle B by extension of turnbuckle 25, motion of movable surface 12below its normal position N-N carries flap l3 with it and. results in anincreasing angular deviation of the flap ii until in some position ofthrow represented by angle X the angular deviation of the said flap I3is as shown by A, of greater magnitude than the original pre-set angleB.

Movement of surface l2 upward from the position just mentioned resultsin a decreasing angular deviation of flap l3. At the normal axis N-Nthis deviation again reaches the pre-set angle B and at some angle Y(determined by the pre-set angle B and the positioning of universaljoint 26 with respect to pivot M) the angular deviation reaches zero sothat movable surface l2 and flap l3 are substantially alined andobliquely disposed above the neutral line NN. It is obvious that thepre-set angle B can be changed or reduced to zero at any timef orrelative positions of the sections of wing l0, controlled as desired bythe pilot.

Referring to Fig. 2 a modification is illustrated wherein the pre-setangle B is duced alined position with respect to movable surface Itwhenever a predetermined angular throw of the movable surface I2 isexceeded. Such a control angle may be of a magnitude of the order ofangle Y as shown and this critical angle Y may be equal or different forthe "up or down positions. o

The mechanism by which the above is made possible consists of a releasecoupling 3! inserted in the shaft 22-just forward of universal joint 26.This coupling has a body portion 42, as shown in Fig. 3 which may bethreaded or otherwise fixed to the forward portion of rod 22, which ofgreater internal diameter than portion of rod 22 carrying universaljoint 26 projects into the hollow body 42 past the said projection 44and carries at its forward extremity a stop ring 43 threaded orotherwise fixed thereon. The purpose'of this ring 43 is to limit theaxial movement of the rear portion of rod 22 with respect to its forward'part by striking either against lug 44 or the forward wall of body 42and also to provide asliding support for rod- 22.

A lug or projection 45, having surfaces substantially parallel to thoseof lug 44, projects from to body portion 42. This projection 45 extendsoutwardly a sufficient distance to insure its contacting one or theother of the opposed faces 44] of lug 44,,yet not so far as to preventits freely sliding within the hollow opening in body 42..

With such a construction as long as the lugs 44 the rearward partaxially approaches or recedes from the forward part to the point wherethe op by the rod each other, then therearward part can rotate apartfrom the forward part of rod 22 and vice versa sothat the flap Hi can beautomatically returned to its neutral in-line position with respect tomovable surface i 2.

. This action is accomplished by a gear segment 4! fixed to flap i3concentrically with its pivot 27 meshing with a Worm-gear 4!! on shaft32. Bearings 33 and 3d mount this shaft 32 within the intermediate wingsection l2 and stop collars 35 prevent any axial movement of the saidrod with the said surface. The end of shaft 32 opposite from worm gear40 connects to universal joint 26 and positioned is a cylindrical bercord or resilient cable 31 passing through sheave 38 to anchor at 39 toa fixed portion Ma of movable surface 12. This cable 31, or any suitabletensioning device such as a spring, is given an initial tension and thenwhenever flap I3 is pro-set to some angle B through manipula tion ofpulley 2| causing rotation of rod 22, cou-' pling 3|, drum 36, drum andtherein.

Whenever the movable surface I2 is swung up or down to its criticalangle Y, as indicated by the dotted position In and'l2d, the couplingstops and 45 thereupon disengage by reason of the axial movement of stop45 induced by the eccentricity of universal joint 26 with respect topivot I4. At this time the tension in cable 31- is free to act on drum36 to rotate it to its neutral position which at the same time restoresflap I3 to its in-line position with respect to movable surface l2. Assoon as the surface l2 passes through the critical angle Y, on beingreturned toward its neutral position, the steps 44 and 45 again reach analignment where they will engage each other and again the line ofcontrol is re-established through coupling 3| so that the flap l3 canbemoved or pre-set by the pilot.

These and other desirable objects and ad vantages of the presentinvention will be illustrated in the accompanying drawing and describedin the specification, a preferred embodiment being disclosed by way ofillustration only, for since the underlying principles may be.incorporated in other specific devices, it is not intended to be limitedto the one here shown, except as such limitations are clearly imposed bythe appended claims.

What we claim is: 1. In an airfoil in combination, a relatively fixedmain section, an intermediate section pivotally fixed thereto, atrailing edge section pivotally attached to the said intermediatesection, and means incorporating release mechanism and operating tovariably determine universal joint 26, rod 32, and hence the rubber cord31 winds up on the coincidentally adds to the tension cally restore thesaid trailing edge section to an alined position with respect to thesaid intermediate section whenever the latter exceeds predeterminedlimits of movement. 7

2. The combination in an airfoil composed of a main portion andarticulated trailing sections comprising a movable surface and a flapmember, of means for raising posed lug faces My and45f no longer contactintermediate these ends drum 36 to which connects a rubing mechanismactuated by movement of the latter surface such that the said flap isreturned to a neutral position on exceeding predetermined limits.

3. The combination in an airfoil, of a fiap pivotally carried by amovable surface, an arm extending from said flap, a control linkageassociated with said arm and incorporating means whereby the angularposition of the said fiap may be set with respect to the said movablesurface and release mechanism and tension means whereby the said flap isautomatically restored to a neutral position whenever movement of themovable surface exceeds predetermined limits.

4. The combination in an airfoil, of a pivoted fiap carried by a movablesurface, control linkage to the pivoted flap whereby the said fiap isadjustably positioned, and means comprising a telescopic coupling,automatically disengaging whenever the said movable surface exceeds apredetermined range of movement, and a tension device operating torestore the said flap to its neutral position on disengagement of saidcoupling, the said means being interconnected with the said controllinkage such that positioning of the said flap angularly to its neutralposition increases the initial tension of the said device.

5. In a variable camber airfoil, a relatively fixed leading airfoilsection, an intermediate movable section pivotally carried at the rearof said leadmeans comprising release mechanism and a re-' storing deviceassociated with said second control means whereby the latter is madeinoperative and the said trailing section is caused to return to analined position with respect to the said intermediate section when thelatter exceeds predetermined rotational movement with respect to saidfixed section.

6. In control mechanism for varying the relative angles of a movablesurface and an auxiliary flap hinged thereto, the combination of atorsion shaft, a releaseable slide coupling associated therewith, andtorsion means operable to rotate a part of said shaft upon release ofsaid coupling whereby the auxiliary fiap is moved relative to saidmovable surface.

7. In a variable camber airfoil consisting of a plurality of sections,adjusting mechanism comprising a torque rod, means for rotating saidrod, connecting links to the trailing section comprising a clutch membernormally engaged but releaseable by movement of an intermediate sectionexceeding predetermined amplitude, torque flap pivoted thereto, thecombination of automatic release mechanism and torque meansautomatically operating upon release of said mechanism to movetheauxiliar'y flap with respect to said movable surface.

9. In an actuating system for aircraft control surfaces, at pivotedconnection to a control surface including a shank member fitted with aninternally threaded sleeve portion adjacent the free end thereof, aconnecting rod having a threaded portion at one end for inter-engagementthe with the said sleeve separation of the said threaded portions, arotatably mounted shaft flexibly connected to the opposite end of saidconnecting rod, and means to cause rotation of said shaft.

10. In a system for aircraft control, the combination with an airfoil ofa movable surface, an auxiliary flap pivoted thereto at a point removedfrom the longitudinal axis of said flap, a control rod extending throughthe leading edge of said fiap and incorporating extensible means wherebythe angular position of said fiap may be set with respect to the movablesurface upon actuation of said means, a second control rod rotatablymounted within the said airfoil and pivotally associated with the firstsaid control rod at a point portion, means to prevent removed from thepivotal axis of the said movable surface whereby movement of the movablesurface progressively changes the angular position of the said fiap.

11. In a system for aircraft control, the combination with an airfoil,of a movable surface, an auxiliary flap pivoted thereto at a pointremoved from the longitudinal axis of said flap, an extensible controlelement extending through the leading edge of said flap andincorporating an internally threaded sleeve portion, a connecting rodthreaded at one end for engagement within the said sleeve portion, meansto prevent disengagement of the said threaded portions, a rotatablymounted shaft flexibly connected to the opposite end of said connectingrod, means to cause rotation of said shaft whereby the angular positionof said fiap'may be set with respect to said movable surface and wherebyupon movement of said movable surface said flap progressively changesits angular position with respect to the set position.

12. In control mechanism for varying the relative angles of a movablesurface and an auxiliary flap hinged thereto, the combination of atorsion shaft, an extensible slide coupling associated therewith, andtorsion means operable to rotate a part of said shaft under control ofsaid coupling, whereby the auxiliary flap is moved relative to saidmovable surface.

13. The combination with an airfoil composed of a main portion andarticulated trailing sections comprising a movable surface and a flapmember, of means for pivotally actuating the said articulated sections,means for variably setting the angular position of the said flap memberwith respect to the said movable surface during flight, and means'presetby said setting means for returning the said flap to its originalposition at a certain position of the said movable surface, all ,of saidmeans being wholly contained within surface outlines of said airfoil.

14. In a variable camber airfoil, a relatively fixed leading airfoilsection, an intermediate movable section pivotally carried at the rearof said moving-section, a trailing section pivotally carried at the rearof said intermediate section, con trolling means for rotating saidintermediate section with respect to said fixed section, second controlmeans including an extensible slide coupling, for rotating the saidtrailing section with respect to said intermediate section and forautotion in an airfoil and a movable surface, an auxiliary flap pivotedthereto at a point removed from 75 the longitudinal axis of said :iiap,an extensible slide coupling extending through the leading edge of saidflap into the interior of said intermediate section, a connecting rodadjustably connected 5 with the slide coupling, a rotatably mountedshaft flexibly attached to the remaining end of said connecting rod andmeans to cause rotation of said shaft, said coupling, connecting rod andshaft all being contained wholly within the sur- 10 face outlines ofsaid airfoil and serving to variably adjust the angular position of saidflap to said movable surface and to automatically return the flap to itsoriginal position at a certain position of the said movable surface.

15 16. In a variable camber airfoil consisting of a tions.

ISAAC M. LADDON. HENRY K. GROWALD.

